It's federal law that prohibits handgun possession of an individual under 21 years old. There's just no way around that no matter what state you live in. Furthermore, if your dad buys one and gives it to you, he'd be breaking federal law as well (straw-purchase). And if he gives it to you and you cross state lines with it, well, you might as well save us all a lot of trouble and just drive both of yourselves down to the nearest federal penitentiary.